That doesn't justify giving them lifetime government enforced monopolies. If they want to keep getting paid, they should have to keep creating new works. Anything else is rent seeking. Having to give them monopolies at all is bad enough but the current state of copyright is completely unacceptable.
Also, their children are owed exactly nothing by society. At most they should be able to inherit still valid copyrights with no change to their durations. Heirs getting a completely new two decade monopoly just so they could "benefit" is absurd and intolerable.
It's "real" because it exists in the real world. It's naturally scarce as a result since two bodies cannot occupy the same space at the same time. There's only so much land available.
It's a completely different matter compared to imaginary artificially scarce cultural property which boils down to ownership of unique numbers. That's what's ridiculous.
Also, their children are owed exactly nothing by society. At most they should be able to inherit still valid copyrights with no change to their durations. Heirs getting a completely new two decade monopoly just so they could "benefit" is absurd and intolerable.